Download

Download Joppa

Pick the file for your system.

Opening Joppa the first time

[macOS]Joppa is not signed by Apple yet, so macOS blocks the first launch. That's expected, and it only asks once.

Install
Open the .dmg file and drag Joppa into the Applications folder.
Launch it, then close the message
Open Joppa. macOS says it was not opened: click “Done”, not “Move to Trash”.
Allow Joppa
Open System Settings › Privacy & Security, scroll down to Security and click “Open Anyway” next to Joppa.
Confirm
Click “Open Anyway” again, then enter your password or use Touch ID. Joppa opens, and opens normally from then on.

On macOS 14 or earlier: right-click Joppa in Applications, choose “Open”, then “Open”.

Comfortable with the terminal? This command lifts the block in one go:

$ xattr -dr com.apple.quarantine /Applications/Joppa.app

AppImage: make the file executable, then run it.

$ chmod +x Joppa_amd64.AppImage
$ ./Joppa_amd64.AppImage

Debian, Ubuntu: install the package.

$ sudo apt install ./Joppa_amd64.deb